


The Zero Law

by MaxKowarth



Series: Sisters Of the Unexplained [3]
Category: Doctor Who, The Omega Factor (TV), UNIT: the New Series (Big Finish Audio)
Genre: Complicated Relationships, Established Relationship, F/F, Jealousy, Mistaken Identity, Misunderstandings, Unexpected revelations, Useless Lesbians, implied infidelity
Language: English
Status: Completed
Published: 2020-06-13
Updated: 2020-06-13
Packaged: 2021-03-03 19:14:58
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,826
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24700672
Author URL: https://archiveofourown.org/users/MaxKowarth/pseuds/MaxKowarth
Summary: If two systems are both in thermal equilibrium with a third system then they are in thermal equilibrium with each other.Thermodynamics apply in all walks of life. Especially it seems, to brilliant scientists working on the edge of human knowledge.A direct sequel to 'The Littlest Thing' not required reading but the series makes sense in order
Relationships: Kate Lethbridge-Stewart/Anne Reynolds (The Omega Factor), Kate Lethbridge-Stewart/Petronella Osgood, Kate Lethbridge-Stewart/Petronella Osgood/Anne Reynolds
Series: Sisters Of the Unexplained [3]
Series URL: https://archiveofourown.org/series/1495040
Comments: 2
Kudos: 5





	The Zero Law

In the cool darkness, far below the Thames, amongst the labyrinthine UNIT facility a tune played.  
‘Need you now’ by Lady Antebellum warbled from a mobile phone for a chorus before starting over.

_“It's a quarter after one, I'm all alone and I need you now  
Said I wouldn't call but I lost all control and I need you now  
And I don't know how I can do without, I just need you now”_

When it was finished the sound of dripping was the only thing left to mask the heaving breath.

\--  
Dr Anne Reynolds sat back on the sofa and scowled at her phone. She should be used to the infuriating state of her girlfriend’s availability but she always took it personally in the last few days of a visit before she returned to work in Edinburgh.  
They had experienced a delicate weekend of emotional and later physical trials. Her beloved Kate Stewart had brought her Head of Projects, Osgood home with her and it had become increasingly clear that a crush on the brilliant brunette was just one more thing Anne shared with her partner.  
They missed Sunday lunch but managed quite an exceptional workout between them all. They were about to start on a delayed pudding that evening when Kate and Os’s phones began ringing simultaneously.  
That’s was nearly 48 hours ago and Anne hadn’t heard from Kate in the last 6.  
She wasn’t worried, of course not as Kate was invincible, but it would be such a comfort to have a text of contact. Just to know she was alive.  
She raised her hand to toss the phone to the coffee table before changing her mind and dialling a new number.

\--

“Osgood’s phone.” A chipper and distinctly male voice answered. “Josh Carter speaking.”  
“Oh, hello. This is Dr Reynolds. I was trying to reach Director Stewart?”  
“Ah.” The young man cleared his throat in almost apologetic manner. “I’m afraid she’s in conference Doctor. They both are.” He added this last in order to explain why he had answered the phone.  
“Is that true or one of those classified above top secret euphemisms you boys like so much?” Anne almost smiled into the phone at the thought of the young captain’s colouring.  
“Actually, as much I enjoy a good euphemism, conference is what I was told. Is it urgent ma’am?”  
Now it was Anne’s turn to blush and she shook her head free of the flirty way he had asked.  
“Not exactly, I was just expecting to hear from her.”  
“I understand you are in the city Dr. Would you like me to send a car? You can meet her when they’ve finished.”  
“I…” Anne was about to refuse but instead said “I would love too, Mr Carter. About time I surprised Kate.”  
“Oh, well if it’s a surprise I’ll fetch you myself.” Carter replied, that same teasing tone in his voice.

\--

Amongst the sound of falling water the shadows stirred; rustling of fabric, moans and the occasional clack of a kitten heel against flagstone.  
Before too long a light broke the darkness. Pale and wan it caused a ghostly face to bob free of context of the mobile’s screen.  
Kate Stewart swore.

\--

Anne found Captain Carter to be gallant, charming and altogether a little too ‘Boys Own’ to fall for.  
“May I ask a question, Ma’am?” he called back from the wheel.  
“Only if you stop calling me that” she teased back. “Go on.”  
“If you were looking for Kate, why did you call Osgood?” Anne boggled. She tried to catch his eye in the mirror but his face was poker straight.  
“Well, they always seemed to be together, right hand woman, you know? So if Kate hadn’t charged her phone then, ‘who ya gonna call?’ right.” She smiled.  
“I was rather under the impression that was your area of expertise Ma... Anne.” He flicked his expression into the cheekiest grin and Anne was sorely tempted to ruffle his hair. Fortunately the car pulled into the secure checkpoint and thereafter into the hidden staging area.  
Carter led her to a small booth where she was given a pass that read ‘Visiting Scientific Specialist class #1’. A short corridor walk and a spiral staircase later Josh waved Anne into Kate’s office.  
“Coffee or something stronger?” He offered and she accepted the coffee, leaving her alone while he went to fetch.  
Anne stared at the office. It wasn’t exactly plush and sparsely decorated. She reasoned that if it was safe to leave her here then nothing on display could possibly be sensitive. A pair of photo frames on the desk caught Anne’s attention and she fought her curiosity briefly before it won out.  
One frame showed a picture from the 00s; Kate, her children, her father, her step mother and her step family. The other, quite to her surprise, appeared to be blank. She reached for it, brushing her thumb over the frame only for the dark surface to swirl and reveal a photo she had never seen of herself and their friend Beth.  
It had clearly been taken during their holiday on Beth’s Spanish farmstead. She remembered that shirt, and what had happened to it. The image showed the two women laughing uproariously and for an instant she could hear the sound of their laughter across the years. She pulled her hand away and the image returned to black.

\--  
Far below Anne a doorway opened and Kate Stewart strode imperiously through it. 20 seconds later it opened once more and Osgood scuttled out, glancing around her and walking in the opposite direction.  


\--

Anne looked up as the door opened, ready to thank Carter for the coffee. She was surprised to find Osgood carrying in the mug.  
“Hello you!” Anne sprang delightedly over to wrap arms around the blushing scientist.  
“Uhm... I brought the coffee?” the younger woman stammered, proffering the mug like a talisman. Anne took it, apologising. She realised that Osgood compartmentalised and must be in work mode right now.  
“Thank you. Any idea how long Kate will be?”  
“I shouldn’t think they will be too much longer. It’s been heavy going and they’ll be glad of the break.” Osgood folded her arms over her jumper and leant against the filing cabinets. Anne tried not to think about the curve of her hip because she knew that way led to madness.  
This was why it took a moment for the woman’s words to sink in.  
“They? I thought…” but whatever she thought was lost as the door swung wide once again to reveal a glowering Kate.  
Dear god the woman was magnificent. Hands in her trouser pockets, blouse loose over the waistband. Her blonde hair swept back and slightly damp. As the two women watched, the scowl evaporated like sun breaking from behind a thundercloud.  
“Anne!” she gasped with unalloyed joy and dashed across to fold her into an adoring embrace. Anne melted into it, her own smile sneaking through the blonde locks across her girlfriend’s shoulder.  
“Sorry I’m late.” Interrupted a familiar voice. Anne opened her eyes to see Osgood straightening her lab coat. Wasn’t she wearing a jumper a moment ago?  
“I’d say you were just in time.” Qualified Osgood still stood by the filing cabinets.  
“Bugger” said Kate Stewart.

\-- 

Anne Reynolds sank backward, fortunately landing on the desk before she could spill her coffee.  
Kate turned back to the lab coated Osgood and ushered her in, making sure the door closed behind them. Anne stared at the room taking in all the details available. Having learnt her lesson at the weekend, she refused to jump to conclusions about the state of the Lab Coated Osgood’s trousers.  
“What a lovely surprise.” Kate continued to smile, removing her jacket to hang on the door. “I know you called earlier but we were busy.”She kept talking, apologising for not getting back to her but Anne wasn’t quite taking in the small talk. Her eyes passed between the three women in the room. The two Osgood’s were whispering conspiratorially and the one in the jumper’s eyes widened before turning to reappraise Dr Reynolds.  
“I imagine you must have questions, darling.” Kate recaptured her girlfriend’s attention with a peck on the cheek. Anne noticed that the smile she was wearing didn’t reach her eyes. At first she couldn’t place the emotion that rested in those usually warm hazel pools.  
Anne decided to start with the obvious. “Two of them?”  
“Yes” Kate confirmed. She couldn’t well deny it.  
“Twins” Anne nods. “Which did…” she started only to spot the flash across Kate’s eyes. She looked over at the two scientists with a sudden drop in her stomach. Back to Kate who made the slightest shake of her head that Anne misconstrued.  
“Oh god, you can’t tell them apart, can you?” the realisation voiced caused both Osgood’s to blush.  
“Of course I can.” Kate dismissed with a wave of her hand. Over her shoulder both of the younger women reacted with genuine surprise. “Don’t you have any questions that aren’t about our Greyhound 2?”  
“Are they Greyhound two because…” Anne waved between the pair.  
“Uh no. Kate’s Greyhound One. It’s a military thing” Osgood said. For the life of her Anne couldn’t tell which one.  
“Are you going to have to wipe my mind?” Anne asked in the smallest voice Kate had ever heard her use.  
“Why? Have you seen something you shouldn’t” Kate replied reassuringly.  
Anne closed her eyes and nodded slowly before replying. “That’s blood on her trousers, isn’t it?”  
Kate stopped. The Osgood’s looked down at the stains on her knees. The three of them all spoke at once, in an identical tone. All of them contradicted each other. Anne, already uncertain and fragile thanks to weekend events, burst into tears.

\--

The Osgood girls diplomatically left the room. Anne suspected they won’t have gone far. Lab Coat Osgood didn’t let her eyes leave Kate until the door reclosed.  
If Kate couldn’t tell them apart, Anne suddenly suspected that she could. And that she knew who had shared their bed.  
“I’ve signed the official secrets act.” Anne admitted out of the blue. Kate looked at her, raising that wicked eyebrow of hers. “I can just go back home, to Edinburgh and keep out of the way. It’s easy to vanish in academia, especially as a woman.”  
Kate burst into that bemusing, gasping honk. “Sorry sweetheart. I’m sorry. We really aren’t going to have to wipe anything. And you don’t have to go anywhere, if you don’t want to.”  
“Why is that funny?” Anne frowned, annoyed that she wasn’t being believed.  
“Oh, that wasn’t. I was just trying to imagine you vanishing! Especially with this,” Kate’s hand reached to tousle Anne’s red curls. The smile was in the blonde’s eyes at last and Anne forced herself to take a breath. “This glorious hair.”  
Anne found herself drawing towards her girlfriend until her breath danced across her lips. “You silly old Ghostbuster.” Kate whispered in prelude to the compelling kiss that blew all other cares away.

\--

“Maybe we should continue this conversation at home?” Kate suggested quite some time later as she did Anne’s blouse back up.  
“I should apologise to Osgood, I’ve made her day... Complicated.” Anne decided.  
“Which one?” Kate teased.  
“Both?” Anne suggested watching Kate closely. “It wasn’t the first time, was it?”  
“That I’ve had to apologise to Os? No, it certainly isn’t.”  
“That wasn’t what I was thinking.” Anne swallowed. “I’ve put two and two together, Kate. You and Osgood are in a relationship, don’t try to deny it.”  
Kate lowered her eyes then looked back up through the blonde locks that conspired against her face.  
“Full disclosure then?” Kate replied seriously. So seriously that Anne felt compelled to take a seat, reaching across the desk to hold her girlfriends hand.  
“I know there are things you just can’t tell me and I respect that. I don’t want to know them. I want to know about us.” Anne pleaded. “I can’t be the girlfriend you deserve. I don’t live here, I don’t work your hours, I can’t give up work and sit in your townhouse waiting for you to return home exhausted after fighting little green men.”  
Kate opened and closed her mouth. Perhaps she had thought it wouldn’t come to this. She closed her hand around Anne’s with the certainty of her decision.

\--

“Osgood is indispensable. I always knew I was attracted to her. But she seemed so totally asexual. Then one day she made a mistake which blew her across a lab.” Kate’s words hitched, clearly reliving the events.  
“That was when I knew it was more than attraction. I’ve lost people in this job and always, always been able to swallow it down and move on. But Osgood, I stayed by her bedside in the infirmary. I recalled some of UNITs best and brightest from across the medical section. I couldn’t imagine a future without Osgood in it so I bent all sorts of rules for her.”  
Anne bit her lip. She hadn’t been expecting a confession. A terse ‘yes’ maybe, but not this.  
“She was unconscious for a week. One of the treatment’s the team introduced raised her ECG, brought her into a light sleep rather than a coma. I thought she was awake, I heard her call my name. She begged for a kiss and…” the words ran out. Kate finally met Anne’s eyes.

“When was this? Recently? I saw the bruise.” Anne pointed to her own collarbone but Kate shook her head, drew a shuddering breath.  
“1992. May Day bank holiday”  
“But the Birmingham conference was 1996…” Anne voiced, she really was the other woman.  
“Anne please. It’s complicated. We, she… It’s not quite love. Not like it is with you it’s... its companionship? Something more… ” her head dropped and the next line was lost into her hair.  
“Sorry?”  
“I said it’s like you and Beth.” Kate’s eyes were on the black photo frame in front of her. 

Anne snatched her hand away, sitting upright and staring at Kate.  
“You knew?” was all the reply she needed to give.  
“I could see it the moment you set eyes on each other. I don’t know how far you went and I don’t want to know. I didn’t have any UNIT calls to Madrid. I just… I wanted you to… ”  
“What? To cheat on you? To fuck your ‘best friend’ the moment your back was turned?”  
“To be happy. To have somewhere to go if… if… ” Kate stopped once more. She sat upright and undid her blouse, pulling it to one side to reveal deep red welts scored across her chest. Anne blanched and reached toward her. 

“Every day Anne, every day might be the one I don’t come home. My people are the best of the best. But we’re all mortal. That’s why I give Osgood whatever she’ll let me. That’s why I introduced you to my childhood girlfriend. But it’s so hard. I love you SO much. And that’s why I try and get you stay every time you visit. Why I indulge your every whim. Why I let your fantasy play out this time. I can’t lose you any more than I can lose Os. We tell people that we are defending the Earth but that’s just the consequences. Every single person here defends one thing; for some it’s themselves, for others its children. For me…” she let her eyes finish the confession. Anne stood, walked around the desk and drew her into a light almost worshipful kiss. Her finger sought the welts on her beloved’s chest and was glad that Kate didn’t flinch away.

“That blood, it was yours?” Kate nodded before replying.  
“Osgood saved me. Had prepped all the kit we might require. Always does. She’s… She’s Os. She’s my Os.”  
“Then I am going to have to thank her, again.” Anne admitted with a sigh.  
“I’ve never told anyone that. Not even her. ”  
“Which one of them?” Anne asked in apparent innocence. That look that failed to be a smile was back in her eyes once again.  
“I can’t tell.” Kate confessed in a hoarse whisper. “And there you have it full disclosure. I’ve not only been in a relationship with my best friend but very possibly with her twin.”

“Thermodynamics.” Anne smiled comfortingly “any two states in equilibrium with a third will also be in equilibrium with each other. You love Osgood, Osgood loves you. I love you, you love me.”  
Kate allowed Anne to pull her head to her bosom as she replied with more than a hint of teasing, “You fantasise about Osgood, She dreams about you. You fall for Beth in love at first sight; Beth is more than prepared to move to Edinburgh if you said so.”  
“What?” Anne pulled back to look at her girlfriend. Kate realised she had that last out loud.  
“Bugger.”

**Author's Note:**

> Written a LONG time ago but posted today as the last of completed Anne Reynolds tales on the anniversary of 'The Omega Factor'.
> 
> There are deliberate gaps in the story that I had planned to revisit but if anyone wants to hear about one of them sooner rather than later, comment below.


End file.
